1c939a53b2
commit 6af3f48bf6156a7f02e91aca64e2927c4bebda03 upstream. WARNING: inconsistent lock state 5.16.0-rc2-syzkaller #0 Not tainted inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. ffff888078e11418 (&ctx->timeout_lock ){?.+.}-{2:2} , at: io_timeout_fn+0x6f/0x360 fs/io_uring.c:5943 {HARDIRQ-ON-W} state was registered at: [...] spin_unlock_irq include/linux/spinlock.h:399 [inline] __io_poll_remove_one fs/io_uring.c:5669 [inline] __io_poll_remove_one fs/io_uring.c:5654 [inline] io_poll_remove_one+0x236/0x870 fs/io_uring.c:5680 io_poll_remove_all+0x1af/0x235 fs/io_uring.c:5709 io_ring_ctx_wait_and_kill+0x1cc/0x322 fs/io_uring.c:9534 io_uring_release+0x42/0x46 fs/io_uring.c:9554 __fput+0x286/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xc14/0x2b40 kernel/exit.c:832 674ee8e1b4a41 ("io_uring: correct link-list traversal locking") fixed a data race but introduced a possible deadlock and inconsistentcy in irq states. E.g. io_poll_remove_all() spin_lock_irq(timeout_lock) io_poll_remove_one() spin_lock/unlock_irq(poll_lock); spin_unlock_irq(timeout_lock) Another type of problem is freeing a request while holding ->timeout_lock, which may leads to a deadlock in io_commit_cqring() -> io_flush_timeouts() and other places. Having 3 nested locks is also too ugly. Add io_match_task_safe(), which would briefly take and release timeout_lock for race prevention inside, so the actuall request cancellation / free / etc. code doesn't have it taken. Reported-by: syzbot+ff49a3059d49b0ca0eec@syzkaller.appspotmail.com Reported-by: syzbot+847f02ec20a6609a328b@syzkaller.appspotmail.com Reported-by: syzbot+3368aadcd30425ceb53b@syzkaller.appspotmail.com Reported-by: syzbot+51ce8887cdef77c9ac83@syzkaller.appspotmail.com Reported-by: syzbot+3cb756a49d2f394a9ee3@syzkaller.appspotmail.com Fixes: 674ee8e1b4a41 ("io_uring: correct link-list traversal locking") Cc: stable@kernel.org # 5.15+ Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/397f7ebf3f4171f1abe41f708ac1ecb5766f0b68.1637937097.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.